London, Zack, Cody and Mr. Moseby set sail on the S.S. Tipton for their semester at sea. London convinces her roomate to leave the ship so she can have a room to herself. Cody finds himself sharing a room with Woody, who is very messy, and Zack shares a room with Bailey, who is a neat freak. Nobody knows that Bailey is a girl who disguised herself as a boy in order to gain a position on the ship after she found that there were no more vacancies for girls. Zack and Cody agree to switch roommates, but Zack changes his mind after he finds out that Bailey is a girl. After everyone else eventually finds this out Bailey is allowed to stay, filling the position vacated by London's ex-roommate, and Bailey becomes London's new roommate. This is the last straw for London and she escapes to Parrot Island via helicopter.

When the ship stops in India, Cody takes Zack with him to visit his guru, a Swami who lives in the top of a mountain who charges high prices for everything he sells. Eventually, Zack and Cody run out of money and join the Swami's worldwide call center. Meanwhile, Mr. Moseby is having computer problems and is trying to contact the call center for help, but without any success. Padma, who was originally London's roommate on the ship, but left after London bribed her, asks London to help convince her mother that she was still at sea. It is later shown that the help center Moseby was calling was run by the Swami, who used an American accent.